The morris pcters cc



' H.-SHAW. I GRINDING MILL.

No. 93,913. Patented M917, 1869.

Letters Patent No 93,913, dated Auoust 17, 1869.

M IMPRO'V'EMIIENlI IN GRINDINQMILL S. w

The Schedule referred to in these Letters Patent and making pan. of thesame.

To all whom it may co-rwern Be it known that I, HENRY SHAW, ofCincinnati,

in the county of Hamilton, and State of Ohio, ha.ve

invented a certain new and useful Improvement in Iron "Grinding-Mills;and I do hereby-declare that the following is a full, clear, and exactdescription of the construction and operation of the same, referencebeing had to the annexed drawings, making part of this specification, inwhich 7,

Figure 1 is a perspective view of a section of a, grinding-plate, A, andsupporting or back -plate, B, both being placed in position to showtheir interioi' surfaces.

Figure 2 is a section of platesA and B, joined together in the usualmanner.

The object of my invention is an iron grinding-mill, thegrinding-surlhces of which shall remain cool during the operation ofgrinding, at the same time dis; pensing with the intermediate layer ofnon-conducting substance, described and claimed in the Letters Patentgranted Henry Shaw and William D. Leavitt, on the 14th day of July,1868.

My means for accomplishing the above purpose is an air-chamber formedbetween the grinding-plates,

respectively, and, the back or supporting-plates.

Projections G and O are formed upon the interior surfaces of thegrinding and back-platcs, as clearly -shown in the drawings.

The plates are circular in form, the projections also are circular, andthe plates, grinding and backeplates, are rigidly attached to eachother, so that none of the material ground or to be ground, may passinto the air-chamber. The well-known low conducting-power of air makesit an efiicient agent for the above-described pnrpose.

Haring. thus described my invention,

What I claim as new, and desire to secure by Letters Patent, is-

An iron grinding-mill, having the projections O and 0' between thegrinding and back-plates, for'the-purpose described. I

HENRY SHAW. Witnesses:

S. S. MORRIS, THEO. ALBERT.

